Poly(dimethylsilylenephenylene) in which a polymeric main chain consists of a repeated structure containing a silicon atom and an aromatic ring is known as a heat-resistant material (e.g. Yamaguchi et al., “KOUBUNSHIKAGAKU” [29] p. 546 and p. 665 (1972) ed. by The Society of Polymer Science, Japan).
In addition, a process for producing poly(dimethylsilylenephenylene) is disclosed, for example, in JP-A-58-55007.